Give embedded metadata its own type instead of relying on EmptyStructTy.

llvm-svn: 72610
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 1ad70df..bfc029c 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -206,6 +206,7 @@
     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
+    case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
     case Type::IntegerTyID:
       // INTEGER: [width]
       Code = bitc::TYPE_CODE_INTEGER;